1. Field of the Invention
The present invention relates to armaments and more particularly to reactive and active armor.
2. Brief Description of Prior Developments
The prior art discloses various arrangements of active armor in which a medial layer is positioned between an outer and an inner armor layer with a medial explosive or non-explosive layer which disrupts a shaped charge to prevent penetration of the overall armor system.
U.S. Pat. No. 4,368,660, for example, discloses an arrangement in which an explosive charge is positioned between two armor layers. On detonation of the explosive, the armor layers are displaced from one another to disrupt the shaped charge jet.
U.S. Pat. No. 4,881,448 discloses an active armor arrangement consisting of two mutually parallel metal plates with an interior sheet of incompressible formaldehyde compound. Upon impact with a hollow jet explosive charge, the incompressible layer causes the outer metal sheets to push outwardly into the path of a hollow jet explosive charge.
U.S. Pat. No. 4,867,077 discloses an active armor in which explosive material is imbedded between layers of a resilient material which are contained between upper and lower rigid plates in a sandwich structure. A construction for application of active armor to a structure to be protected comprises a plurality of such packages, a plurality of projections attached to the structure and a plurality of holder each attachable to the other and running between adjacent projections. Each of the holders holds an edge of one of the packages so that each projection is thereby attached to at least one of the packages by the holder.
It has also been suggested that performance of active armor may be improved by providing a medial space between an outer and an inner armor layer and providing an electrical generator to create an electric or magnetic field in the space between the outer and inner armor layers. A disadvantage to such an arrangement might be that the necessity to add additional weight and space requirement in order to provide an electrical generator of sufficient capacity to provide the necessary parent supply might add undue weight and space requirements when such an armor is used on a mobile vehicle. A further disadvantage of such an arrangement might be that the effectiveness of such armor might be reduced or effectively lost in the event of a power failure during operations, or in the event that the generator was shut down during non-operational periods.
A need, therefore, exists for active armor in which an electrical or magnetic field may be provided in the space between an outer and inner armor layers which is not dependent on a necessity to be continually generating electrical power.
The present invention is an active armor system, which includes a first armor layer and a second armor layer. A space is interposed between the first and second armor layer. A third layer is also positioned preferably adjacent to and on the inner side of the first layer. This third layer is comprised of a material selected from a piezoelectric material, an electrostrictive material, and a magnetostrictive material. The third layer may also be characterized as any material capable of producing an electrical or magnetic field within the space in response to the application of mechanical force on this third layer. The application of force on the third layer as a result of the impacting of a shaped charge projectile on the first armor layer will result in the production of an electric or magnetic charge in the interior space which will disrupt the formation of the shaped charge gas jet so as to prevent the penetration of the second armor layer.